This is a proposal to investigate the fine structure and synaptology of certain central nervous system centers (caudate nucleus, putamen, globus pallidus, substantia nigra, subthalamic nucleus, red nucleus, the thalamic nuclei: centrum medianum and the divisions of the ventralis anterior-ventralis lateralis complex) with the Golgi technique and electron microscopy. Used in combination, thick Golgi sections and ultra-thin electronmiroscopic sections complement each other and provide a potent means of investigation. The value of this approach is now more widely appreciated than it was a few years ago. Thus, Palay (1965), commenting on the uni-cellular recording methods in electrophysiology, notes: "The refinement of detail now obtainable in morphology and physiology makes it imperative that the investiation of the architecture of the nervous system by means of optical microscopy should be intensified, especially using Golgi techniques." An underlying theme in this morphological study will be Ramon y cajal's (1954) classification of synapses. This classfication based on the geometry of the neuronal elements involved and described in detail in his last monograph, "Neuron Theory or Reticular Theory?" (English translation: M. Ubeda-Purkiss and C.A. Fox, 1954) has in our opinion, never been fully appreciated or exploited. Our long-term goal is to contnue invesdigating the fine structure of central nervous system centers relying on clues supplied by Golgi preparations already available in our laboratory and Golgi preparations to be obtained in the future. This is a broad statement of our objectives.